89 (number)

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 ← 88 89 90 →
Cardinaleighty-nine
Ordinal89th
(eighty-ninth)
Factorizationprime
Prime24th
Divisors1, 89
Greek numeralΠΘ´
Roman numeralLXXXIX
Binary10110012
Ternary100223
Quaternary11214
Quinary3245
Senary2256
Octal1318
Duodecimal7512
Vigesimal4920
Base 362H36

89 (eighty-nine) is the natural number following 88 and preceding 90.

In mathematics

89 is:

${\displaystyle {\frac {1}{89}}=\sum _{n=1}^{\infty }{F(n)\times 10^{-(n+1)}}=0.011235955\dots \ .}$
• a Markov number, appearing in solutions to the Markov Diophantine equation with other odd-indexed Fibonacci numbers.

M89 is the 10th Mersenne prime.

Although 89 is not a Lychrel number in base 10, it is unusual that it takes 24 iterations of the reverse and add process to reach a palindrome. Among the known non-Lychrel numbers in the first 10000 integers, no other number requires that many or more iterations. The palindrome reached is also unusually large.[4]

Eighty-nine is:

In other fields

Eighty-nine is also: